Activation of cholinergic receptors

• Called cholinomimetics

• Direct acting: produce their effects by binding to and activating cholingergic receptors

• Tertiary amines are able to penetrate the BBB

• Divided into:

  • Muscarinic antagonists: M2 and M3 mediate at peripheral tissues, M1 and M3 abundant in brain and autonomic ganglia

    • Effects: constriction of the iris sphincter, contraction of the ciliary muscle resulting in accommodation of the lens, constriction of the airways, increase in GI motility, contraction of the bladder, decreases in heart rate, increase in the secretion of sweat glands, salivary glands, lacrimal glands and glands of the tracheal and GI mucosa, relaxation of blood vessels by M3

• Nicotinic agonists:

• Contraction then depolarisation blockade and paralysis

• Effects: elevates blood pressure and heart rate, diarrhea and urination, in brain causes alertness, vomiting, tremors, convulsions, and coma

Category: Pharmacology Notes